Wet wipes are typically premoistened, disposable towelettes which may be utilised in a variety of applications both domestic and industrial and perform a variety of functions. Wet wipes are typically used to wipe surfaces both animate and inanimate, and may provide numerous benefits such as cleaning, cleansing, disinfecting, and skin care benefits.
One particular application is the use of wet wipes for wiping parts of the human body particularly when wash water is not available, for example when traveling. Wipes are commonly used for human cleansing and wiping such as anal, perineal cleansing and genital cleansing and face and hand cleansing for example as intimate hygiene wipes such as feminine wet wipes. Wet wipes may also be used for application of substances to the body including removing and applying of make-up, skin conditioners and medications. Another application of wipes is during diaper changes and also for the treatment of adult and baby dermatitis partly caused by the use of diapers and incontinence devices. In addition wet wipes are also applicable for wiping and or cleaning other surfaces or for the application of compositions to surfaces, for example kitchen and bathroom surfaces, eyeglasses, shoes and surfaces which require cleaning in industry for example surfaces of machinery or automobiles. Wet wipes also include articles used for the cleaning or grooming of pets.
Wet wipes are commonly constructed of combinations of synthetic and natural fibres, such as polyolefin fibres, viscose fibres and cotton fibres, which are generally moistened with an aqueous composition which contains amongst others surfactants, preservatives, oils and scents. The wet wipes are then typically provided in a folded stacked configuration within a covered container such as a tub-like container having a lid. Alternatively, the wipes may be provided in tub containers having a dispensing aperture. In both cases this allows easy transportation and storage of the wipes.
However, a problem with the current stacking of folded wet wipes is the lack of easy, single wipe dispensation from the wet wipe stack. This problem is particularly acute in circumstances of use such as when a consumer is holding a baby during a diaper change. Under such conditions the consumer needs to be able to pick up and separate the wipe from the stack using only one hand. This is not achieved satisfactorily with current products.
The problem of the lack of satisfactory wet wipe dispensation from the stack and container is due to a number of reasons. Firstly, wet wipes are typically folded and either placed one on top of the other or interleaved with an adjacent wipe. However, the exact location of the leading edge of the upper most wipe of the current stack is not easily identifiable, either visually or tacitly. This is because the substrate material of the wipe is typically homogeneous and thus the leading edge of the wipe, particularly when folded, cannot be distinguished from the wipe substrate material on which it rests. In addition, the leading edge portion of the wipe also has a tendency to adhere to the underlying wipe substrate material on which it rests. Hence even tactile identification of the edge by running or dragging of the fingers across the wipe surface does not immediately result in the identification of the location of the edge.
Secondly, once the leading edge has been located, it is difficult for the consumer to grasp hold of sufficient substrate material and maintain grasp thereof, in order to separate a single wipe from the stack upon which it rests. The consumer often is only able to grasp a small portion of the leading edge such that a tight grip thereof is not established and hence the wipe easily slips from the fingers of the consumer.
These problems associated with wet wipe dispensation have been recognised in the art. For example U.S. Pat. No. 5,540,332 addresses dispensability of wet wipes and a method of producing these wipes. The improved dispensability is achieved by providing at least a portion of one of the end edges of the wipe with a repeating non-linear pattern such as a sine wave configuration. However, the problem of single wet wipe dispensation is neither addressed or overcome by the use of a non linear leading edge.
Another proposed solution to the dispensing problem is described in U.S. Pat. No. 4,778,048, which discloses a product comprising a stack of wet wipes tilted on edge within a container for improved access, dispensing and equal liquid distribution. In a preferred embodiment, the edge of each wipe has a Gurley Stiffness greater than the stiffness of the main body of the wipe. However, the provision of such a stiff edge is in itself undesirable characteristics of a wet wipe. Wet wipes, particularly those intended for use on sensitive areas of the skin such as baby wipes require a certain degree of softness. The edge of the wipe which is stiffened is no longer suitable for use as is indeed recognised in the patent itself, and hence the wipes have a reduced substrate surface suitable for use. Also care needs to be taken to reduce or avoid contact of this edge portion with the skin as it may cause irritation. Moreover, the stiffness of the edge again does not solve the problem of single wipe dispensation. In addition, the provision of such a non linear edge on a nonwoven substrate using current manufacturing techniques would also result in the fraying of the edges of the substrate which is also highly undesirable.
Alternatively, it has also been proposed to provide specifically designed dispensing containers having dispensing orifices in order to aid in the identification of the leading edge by the consumer. These containers are designed such that during the removal action of the upper most wipe from the container, the adjacent wipe is elevated from the stack such that it partially protrudes through the orifice once the upper most wipe has been removed. In this manner the uppermost wipe is positioned for easy grasp by the consumer. However, a disadvantage with such devices is that too much substrate material of the adjacent wipe is exposed through the orifice. Accordingly, the wipe becomes dry and unsuitable for use and has to be discarded. EP 747 313 proposes a means to address this problem and discloses a multiple folded paper, such as wetted tissue paper, for continuous disposal through a container orifice. In this manner a maximum of a quarter of the length of the adjacent wipe is exposed through the dispensing orifice. However, such paper tissue products cannot be utilised for all wet wipe applications, such as baby wipes as the wetted tissue paper is not satisfactory in terms of softness or strength. In particular, such wetted tissues suffer from a tendency to tear during use and hence are not suitable for use as wet wipes.
Another key contributory factor to the problem of single wet wipe dispensation from the wet wipe stack which is not addressed by any of the foregoing prior art, is the tendency of the wipe substrate material to adhere to itself. In particular, this is due to the compression of the wipe stacks during manufacture and storage, the actual weight of the stack of wipes themselves, and the existence of attractive forces in-between the substrate material and the lotion of the wipes. As a result, when the wipes are folded to form a stack, the substrate material tends to adhere to itself and the substrate material of adjacent wipes. Consequently, once the consumer has raised the wipe from the stack, the wipe tends to maintain its folded configuration. Moreover, the wipe typically remains at least partially adhered to the adjacent wipe on which it was resting. Hence, in addition during the action of wipe removal from the stack, the adjacent wipe is also at least partially separated from the stack. As a result the consumer is required not only to unfold the wipe before commencing with the desired application of the wipe but also, to separated it from the adjacent wipe in the stack and returned this wipe to the stack in the container. This is obviously particularly inconvenient to consumers utilising baby wipes during diaper changes.
The problem of substrate wipe adhesion has been recognised in the prior art. Attempts at resolving this problem have typically resided in the provision of interleaved wipes as for example described in JP 08 089 439. Indeed interleaving is also known in the prior art related to dry tissue products such as disclosed in U.S. Pat. No. 2,772,021 and U.S. Pat. No. 3,330,553. However due to complex interactions that exist between substrate material and lotion in the wet wipe product, it is known that the folding configurations generally utilized in such dry tissue products cannot be reapplied to wet wipes.
Furthermore, many of the proposed interleaving configurations have associated problems therewith. In particular, when as a result of interleaving the degree of overlap of substrate material between adjacent wipes is large, then the problem of substrate adhesion is merely exacerbated such that the wipes are effectively always released in pairs, or although the wipe is dispensed singly, a large proportion of an adjacent wipe may still be exposed through the dispensing orifice after the removal of the upper wipe, such that the wipe becomes dry. On the other hand, if the overlap between adjacent wipes is minimised such that single wipe dispensation is guaranteed, there is no recognisable separation of the adjacent wipe from the stack and the problem of leading edge identification reappears.
Furthermore, in addition to the unsatisfactory dispensation of the wipes, other problems related to the proposed prior art interleaving configurations may also arise. For example, as a result of the interleaving configurations the substrate material may be unevenly distributed in the container, which leads to a number of undesirable effects such as uneven lotion distribution throughout the stack of wipes and within the individual wipes themselves resulting in concentration of the lotion at specific areas within the stack. Moreover, many of the interleaving configurations also result in the formation of ridges and grooves in the substrate material, which both tends to reduce the strength and softness of the wipe in addition to being aesthetically undesirable.
It is therefore desirable to provide a wet wipe substrate which is suitable for multiple applications such as baby wipes, which are strong, soft and absorbent. It is further desirable to provide a stacking configuration for such wet wipes which faciliates easy, single wipe dispensation from the wipe stack.
The present invention addresses these problems by providing a stack of wet wipes which have an improved folding and interleaving configuration.